Email authentication, or validation, is a collection of techniques aimed at equipping messages of the email transport system with verifiable information about their origin.

It is a coarse-grained authentication, usually at Administrative Management Domain (ADMD).

Electronic spamming is the use of electronic messaging systems to send an unsolicited message (spam), especially advertising, as well as sending messages repeatedly on the same site.

While the most widely recognized form of spam is email spam, the term is applied to similar abuses in other media: instant messaging spam, Usenet newsgroup spam, Web search engine spam, spam in blogs, wiki spam, online classified ads spam, mobile phone messaging spam, Internet forum spam, junk fax transmissions, social spam, spam mobile apps, television advertising and file sharing spam.

It is named after Spam, a luncheon meat, by way of a Monty Python sketch about a menu that includes Spam in every dish.

The food is stereotypically disliked/unwanted, so the word came to be transferred by analogy.

In computer programming, an Application Programming Interface (API) is a set of subroutine definitions, protocols, and tools for building application software.

In general terms, it is a set of clearly defined methods of communication between various software components.

A good API makes it easier to develop a computer program by providing all the building blocks, which are then put together by the programmer.

The General Data Protection Regulation (GDPR) (Regulation (EU) 2016/679) is a regulation by which the European Parliament, the European Council and the European Commission intend to strengthen and unify data protection for individuals within the European Union (EU).

It also addresses the export of personal data outside the EU.

The primary objectives of the GDPR are to give citizens back control of their personal data and to simplify the regulatory environment for international business by unifying the regulation within the EU.

When the GDPR takes effect it will replace the data protection directive (officially Directive 95/46/EC) from 1995.

The regulation was adopted on 27 April 2016.

It applies from 25 May 2018 after a two-year transition period and, unlike a directive, it does not require any enabling legislation to be passed by national governments.

In computer science, real-time computing (RTC), or reactive computing describes hardware and software systems subject to a "real-time constraint", for example from event to system response.

Real-time programs must guarantee response within specified time constraints, often referred to as "deadlines".

The correctness of these types of systems depends on their temporal aspects as well as their functional aspects.

Real-time responses are often understood to be in the order of milliseconds, and sometimes microseconds.

A system not specified as operating in real time cannot usually guarantee a response within any timeframe, although actual or expected response times may be given.